UN High Commissioner for Refugees Antonio Guterres has said that the number of refugees from Syria could double or even triple by the end of the year if the exodus continues at the present rate.

More than 1 million Syrians have been registered as refugees since the fighting began in their country two years ago.

Speaking in Ankara, Guterres called for increased international support for the countries most affected by the refugee crisis -- Turkey, Lebanon, and Jordan.

Meanwhile, the London-based Syrian Observatory for Human Rights said forces fighting against the government of President Bashar al-Assad launched an attack against the Bab Amr neighborhood of the city of Homs on March 10.

Opposition troops were driven out of the former stronghold last year after more than a month of heavy fighting.